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Not in CISA KEV
HIGH severity

CVE-2023-25577 — werkzeug

HIGHFix: pallets/werkzeug@517cac5

CVE-2023-25577 is a high-severity (CVSS 7.5) CWE-770 vulnerability in werkzeug. A fix is available for werkzeug — see the affected versions and patch details below.

Werkzeug may allow high resource usage when parsing multipart form data with many fields

Also known asGHSA-xg9f-g7g7-2323PYSEC-2023-58
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-25577.

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs73th percentile — riskier than 73% of all scored CVEsHighest risk
0.00%0.64%1.28%1.92%0.4%1.4%Jun 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐍werkzeug

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Werkzeug is a comprehensive WSGI web application library. Prior to version 2.2.3, Werkzeug's multipart form data parser will parse an unlimited number of parts, including file parts. Parts can be a small amount of bytes, but each requires CPU time to parse and may use more memory as Python data. If a request can be made to an endpoint that accesses request.data, request.form, request.files, or request.get_data(parse_form_data=False), it can cause unexpectedly high resource usage. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. The amount of RAM required can trigger an out of memory kill of the process. Unlimited file parts can use up memory and file handles. If many concurrent requests are sent continuously, this can exhaust or kill all available workers. Version 2.2.3 contains a patch for this issue.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIwerkzeugall versions2.2.3pip install --upgrade 'werkzeug==2.2.3'

Affected Products

1 product · 1 configurations
Application
werkzeugpalletsprojects
< 2.2.3
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for werkzeug, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update werkzeug to 2.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-25577 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant
ProductFixed inAdvisory
Ironic content for Red Hat OpenShift Container Platform 4.11python-werkzeug-0:2.0.3-5.el8RHBA-2023:1759
Ironic content for Red Hat OpenShift Container Platform 4.12python-werkzeug-0:2.0.3-4.el9RHBA-2023:1507
Ironic content for Red Hat OpenShift Container Platform 4.13python-werkzeug-0:2.0.3-4.el9RHSA-2023:1325
Red Hat Ceph Storage 7.1oath-toolkit-0:2.6.12-1.el8cpRHSA-2025:4664
Red Hat Ceph Storage 8.1oath-toolkit-0:2.6.12-1.el9cpRHSA-2025:9775
Red Hat OpenShift Container Platform 4.14python-werkzeug-0:2.2.3-2.el9RHSA-2023:7473
Red Hat OpenStack Platform 13.0 Octavia - ELSpython-werkzeug-0:0.14.1-3.1.el7ostRHSA-2023:1281
Red Hat OpenStack Platform 17.0python-werkzeug-0:2.0.1-5.el9ostRHSA-2023:1018

Frequently Asked Questions

Werkzeug is a comprehensive WSGI web application library. Prior to version 2.2.3, Werkzeug's multipart form data parser will parse an unlimited number of parts, including file parts. Parts can be a small amount of bytes, but each requires CPU time to parse and may use more memory as Python data. If a request can be made to an endpoint that accesses `request.data`, `request.form`, `request.files`, or `request.get_data(parse_form_data=False)`, it can cause unexpectedly high resource usage. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that
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CVE-2023-25577: werkzeug DoS — Fixed in 2.2.3